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Message-ID: <4af13376567f83331a9372ae2bb25e11a3d0f055.1742852846.git.jpoimboe@kernel.org>
Date: Mon, 24 Mar 2025 14:55:53 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
Miroslav Benes <mbenes@...e.cz>,
Brendan Jackman <jackmanb@...gle.com>,
Nathan Chancellor <nathan@...nel.org>
Subject: [PATCH 03/22] objtool: Ignore entire functions rather than instructions
STACK_FRAME_NON_STANDARD applies to functions. Use a function-specific
ignore attribute in preparation for getting rid of insn->ignore.
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
tools/objtool/check.c | 35 +++++++++++++++--------------
tools/objtool/include/objtool/elf.h | 1 +
2 files changed, 19 insertions(+), 17 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 33beefd459a6..8e2f3405d78c 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -981,7 +981,6 @@ static int create_direct_call_sections(struct objtool_file *file)
*/
static void add_ignores(struct objtool_file *file)
{
- struct instruction *insn;
struct section *rsec;
struct symbol *func;
struct reloc *reloc;
@@ -1008,8 +1007,7 @@ static void add_ignores(struct objtool_file *file)
continue;
}
- func_for_each_insn(file, func, insn)
- insn->ignore = true;
+ func->ignore = true;
}
}
@@ -1620,6 +1618,7 @@ static int add_call_destinations(struct objtool_file *file)
struct reloc *reloc;
for_each_insn(file, insn) {
+ struct symbol *func = insn_func(insn);
if (insn->type != INSN_CALL)
continue;
@@ -1630,7 +1629,7 @@ static int add_call_destinations(struct objtool_file *file)
add_call_dest(file, insn, dest, false);
- if (insn->ignore)
+ if (func && func->ignore)
continue;
if (!insn_call_dest(insn)) {
@@ -1638,7 +1637,7 @@ static int add_call_destinations(struct objtool_file *file)
return -1;
}
- if (insn_func(insn) && insn_call_dest(insn)->type != STT_FUNC) {
+ if (func && insn_call_dest(insn)->type != STT_FUNC) {
WARN_INSN(insn, "unsupported call to non-function");
return -1;
}
@@ -3478,6 +3477,9 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
u8 visited;
int ret;
+ if (func && func->ignore)
+ return 0;
+
sec = insn->sec;
while (1) {
@@ -3723,7 +3725,7 @@ static int validate_unwind_hint(struct objtool_file *file,
struct instruction *insn,
struct insn_state *state)
{
- if (insn->hint && !insn->visited && !insn->ignore) {
+ if (insn->hint && !insn->visited) {
int ret = validate_branch(file, insn_func(insn), insn, *state);
if (ret)
BT_INSN(insn, "<=== (hint)");
@@ -3937,10 +3939,11 @@ static bool is_ubsan_insn(struct instruction *insn)
static bool ignore_unreachable_insn(struct objtool_file *file, struct instruction *insn)
{
- int i;
+ struct symbol *func = insn_func(insn);
struct instruction *prev_insn;
+ int i;
- if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP)
+ if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP || (func && func->ignore))
return true;
/*
@@ -3959,7 +3962,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
* In this case we'll find a piece of code (whole function) that is not
* covered by a !section symbol. Ignore them.
*/
- if (opts.link && !insn_func(insn)) {
+ if (opts.link && !func) {
int size = find_symbol_hole_containing(insn->sec, insn->offset);
unsigned long end = insn->offset + size;
@@ -3985,19 +3988,17 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
*/
if (insn->jump_dest && insn_func(insn->jump_dest) &&
strstr(insn_func(insn->jump_dest)->name, ".cold")) {
- struct instruction *dest = insn->jump_dest;
- func_for_each_insn(file, insn_func(dest), dest)
- dest->ignore = true;
+ insn_func(insn->jump_dest)->ignore = true;
}
}
return false;
}
- if (!insn_func(insn))
+ if (!func)
return false;
- if (insn_func(insn)->static_call_tramp)
+ if (func->static_call_tramp)
return true;
/*
@@ -4028,7 +4029,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
if (insn->type == INSN_JUMP_UNCONDITIONAL) {
if (insn->jump_dest &&
- insn_func(insn->jump_dest) == insn_func(insn)) {
+ insn_func(insn->jump_dest) == func) {
insn = insn->jump_dest;
continue;
}
@@ -4036,7 +4037,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
break;
}
- if (insn->offset + insn->len >= insn_func(insn)->offset + insn_func(insn)->len)
+ if (insn->offset + insn->len >= func->offset + func->len)
break;
insn = next_insn_same_sec(file, insn);
@@ -4128,7 +4129,7 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
return 0;
insn = find_insn(file, sec, sym->offset);
- if (!insn || insn->ignore || insn->visited)
+ if (!insn || insn->visited)
return 0;
state->uaccess = sym->uaccess_safe;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 4edc957a6f6b..eba04392c6fd 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -68,6 +68,7 @@ struct symbol {
u8 embedded_insn : 1;
u8 local_label : 1;
u8 frame_pointer : 1;
+ u8 ignore : 1;
u8 warnings : 2;
struct list_head pv_target;
struct reloc *relocs;
--
2.48.1
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